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Tire hitting down tube

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05 Aug 2023 12:57 - 05 Aug 2023 12:59 #887983 by ckahleer
Tire hitting down tube was created by ckahleer
This is another progect in the garage. NT125. The fork tubes are straight. But when forks are compressed,the tire hits the down tube. Manual lists wheel base to be 52" but I measure 49.5".I don't know the history of this bike, but it think it took a front end hit sometime.Am I screwed.

94 KE100
81 CM200t
82 KZ305
85 VF1100c
Last edit: 05 Aug 2023 12:59 by ckahleer.

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05 Aug 2023 13:07 #887984 by Nerdy
Replied by Nerdy on topic Tire hitting down tube
The triple clamps are bent, or the frame is bent, or both.

If the triple clamps are bent, you can replace them.

If the steering head (i.e. frame) is bent then you might be screwed depending on how you want to use the bike and how much you want to spend on it.

1979 KZ400 Gifted to a couple of nephews
1967 Yamaha YCS1 Bonanza
1980 KZ440B
1981 Yamaha XT250H
1981 KZ440 LTD project bike
1981 GPz550
2013 Yamaha FZ6R

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05 Aug 2023 14:24 #887986 by zed1015
Replied by zed1015 on topic Tire hitting down tube
The angle of the forks look to be steeper than the head stock.
It's clearly had a front end shunt and at the least the bottom yoke has been bent /pushed back and likely the forks too.

AIR CORRECTOR JETS FOR VM CARBS AND ETHANOL RESISTANT VITON CHOKE PLUNGER SEAL REPLACMENT FOR ALL CLASSIC AND MODERN MOTORCYCLE CARBURETTORS
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  • Scirocco
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  • Never change a running system
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05 Aug 2023 18:23 #887987 by Scirocco
Replied by Scirocco on topic Tire hitting down tube
The frame/head stock area is bend!!!

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  • Ojisan rider
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05 Aug 2023 21:06 #887991 by Ojisan rider
Replied by Ojisan rider on topic Tire hitting down tube
Is it just me or the down tube coming out from the steering head looks bent? Or welded.

I thought on most bikes, that part of the frame is straight...................

Could be my eyes. I'm getting old....................

82' KZ750-R1 cafe racer style. Clip-on, Rear set, Fork-Brace, Mikuni Flat-slide (forgot the size), Kerker.
84' GPz750 (basket case). everything are in pieces.
89' ZX750-H1 (ZX-7 Ninja). Resurrection project are on going with my KZ750. Everything is stock.

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06 Aug 2023 02:27 - 06 Aug 2023 02:30 #887992 by Warren3200gt
Replied by Warren3200gt on topic Tire hitting down tube
It's fooked! 
A picture from the front with the bike upright showing wheel alignment will show if the frame is twisted. 


Z1000J2 somewhat modified!

Last edit: 06 Aug 2023 02:30 by Warren3200gt.

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06 Aug 2023 12:00 #887998 by Nerdy
Replied by Nerdy on topic Tire hitting down tube

It's fooked! 
 

Not necessarily. As I said above, if the only thing wrong is that the triple clamps are bent, they can be replaced; this will return the front end to its proper geometry.

When I was a teenager, a ditch jumped out in front of me and grabbed the front wheel of my enduro bike: the bike stopped immediately but I went on a short flight. :) Both triple clamps actually broke but the frame itself was fine.

1979 KZ400 Gifted to a couple of nephews
1967 Yamaha YCS1 Bonanza
1980 KZ440B
1981 Yamaha XT250H
1981 KZ440 LTD project bike
1981 GPz550
2013 Yamaha FZ6R

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  • SWest
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  • 10 22 2014
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06 Aug 2023 13:49 #888004 by SWest
Replied by SWest on topic Tire hitting down tube
Looks like the steering head caved, the fork assy was replaced and the bike sold. 
Steve
The following user(s) said Thank You: sf4t7, Wookie58

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06 Aug 2023 14:13 - 06 Aug 2023 14:15 #888005 by ckahleer
Replied by ckahleer on topic Tire hitting down tube
I'm tearing the front down now. I may get lucky and just need to replace the tripple tree. I lowered the tubes and clamped them in the bottom clamps. see pic.
Can't see how you can bend the tripple tree without bending the tubes. PO must have just replaced the tubes and didn't fix the tripple tree. Tubes are newish looking.

94 KE100
81 CM200t
82 KZ305
85 VF1100c
Last edit: 06 Aug 2023 14:15 by ckahleer.

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  • SWest
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  • 10 22 2014
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06 Aug 2023 16:17 #888010 by SWest
Replied by SWest on topic Tire hitting down tube
Looks like everything has a slight bend to them. 
Steve

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06 Aug 2023 16:18 #888011 by zed1015
Replied by zed1015 on topic Tire hitting down tube
Frame is bent at the neck.
Top tube should be straight but is arched upward and the downtube is bent rearwards with the headstock bracing distorted and splayed behind the bottom bearing too.
Cross brace above the engine looks to be bent upwards also.
Those forks have been replaced after the event.
Probably thought it was just the forks that were bent until the new/repaired ones were fitted..

AIR CORRECTOR JETS FOR VM CARBS AND ETHANOL RESISTANT VITON CHOKE PLUNGER SEAL REPLACMENT FOR ALL CLASSIC AND MODERN MOTORCYCLE CARBURETTORS
kzrider.com/forum/23-for-sale/611992-air-corrector-jets-





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06 Aug 2023 17:58 #888012 by ckahleer
Replied by ckahleer on topic Tire hitting down tube

Frame is bent at the neck.
Top tube should be straight but is arched upward and the downtube is bent rearwards with the headstock bracing distorted and splayed behind the bottom bearing too.
Cross brace above the engine looks to be bent upwards also.
Those forks have been replaced after the event.
Probably thought it was just the forks that were bent until the new/repaired ones were fitted..
Sounds like a bent tripple tree is the least of my problems. Thanks all for the help. Not sure how I'll procede. I'll think on it awhile.
 

94 KE100
81 CM200t
82 KZ305
85 VF1100c

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